Textile treatment compositions suitable for providing fabric softening and static control benefits during laundering are well-known in the art and have found wide-scale commercial application. Conventionally, rinse-added fabric softening compositions contain, as the active softening component, substantially water-insoluble cationic materials having two long alkyl chains. Typical of such materials are di-stearyl di-methyl ammonium chloride and imidazolinium compounds substituted with two stearyl groups. These materials are normally prepared in the form of a dispersion in water and it is generally not possible to prepare such aqueous dispersions with more than about 10% cationic material without encountering intractible problems of product viscosity and stability, especially after storage at elevated temperatures, such that the compositions are unpourable and have inadequate dispensing and dissolving characteristics in rinse water. This physical restriction on softener concentration naturally limits the level of softening performance achievable without using excessive amounts of product, and also adds substantially to the costs of distribution and packaging. Accordingly it would be highly desirable to prepare physically-acceptable textile treatment compositions containing much higher levels of water-insoluble cationic softener materials.
The problem of preparing fabric softening compositions in concentrated form suitable for consumer use has already been addressed in the art, but the various solutions have not been entirely satisfactory. It is generally known (for example in U.S. Pat. No. 3,681,241) that the presence of ionizable salts in softener compositions does help reduce viscosity, but this approach is ineffective in compositions containing more than about 12% of dispersed softener, in as much as the level of ionizable salts necessary to reduce viscosity to any substantial degree has a seriously detrimental effect on product stability.
In European Published Patent Application No. 406 concentrated fabric softeners are disclosed which comprise three active softening ingredients, one of which is a highly soluble cationic fabric substantive agent. While such compositions do allow a high concentration of active ingredient, their overall softening performance is less effective than is the case with compositions containing predominantly a water-insoluble cationic softener. In European Patent Application No. 13780, the use of low levels of paraffinic hydrocarbons, fatty acids, fatty acid esters and fatty alcohols as viscosity control agents for concentrated softener compositions is described. It has been found, however, that although these materials are excellent in reducing the viscosity of concentrated fabric softener compositions at temperatures below the Krafft point of the cationic softener, they are very much less effective as viscosity reducing agents at temperatures close to or above the Krafft point of the softener.
It has now been discovered that viscosity control in concentrated fabric softener compositions can be significantly improved, both at normal and higher temperatures, without detrimentally effecting product stability, by the addition thereto of a low level of certain alkoxylated amines, or the ammonium derivatives thereof. While the use of alkoxylated amines, as a class, in detergent and softener compositions is not new (see, for instance, German Patent Application Nos. 2829022 and 1,619,043 and U.S. Pat. Nos. 4,076,632 and 4,157,307), it appears that the value of the alkoxylated amines specifically defined herein as additives for controlling the viscosity and stability of concentrated softener compositions, has hitherto not been recognized in the art.
The present invention thus provides a concentrate aqueous textile treatment composition having improved viscosity characteristics at both normal and elevated temperatures and having good storage stability and other physical characteristics necessary for consumer use. The present invention also provides a cost-efficient, physically-acceptable concentrated textile treatment composition providing softening and anti-static benefits across the range of natural and synthetic fabric types, based on water-insoluble cationic softener as the major active component of the composition.